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401 daily driving


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i have a 65 riv. rebuilt 401 with 1000 miles. what kind of gas. i have been running premium and this tank i have tried regular. what is the difference? i am getting 10mpg in town. is that it or do i have a performance issue? what should the plug life be using unleaded gas. i only change the plugs once a year on my newer vehicles.<BR>my clear fuel filter is dry sometimes. where is the gas going? when the car is hot it takes some pumping to get it started. cold starts are a touch only. oil recommendations?<BR>does any of the mileage helpers tricks work on these old babys?

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  • 3 weeks later...

Use my '66 Skylark GranSport as a "daily driver" so I have a few thoughts. Use Premium fuel as the compression should be 10.25. I've converted to a Pertronix electronic ign, re-curved the dist, and set total timing on my 401 @30. NO pinging and has plenty o'pep. Unleaded is better for the plugs but, won't last as long on a point-type ign. Your restart problem sounds like the carb needs a rebuild and set to proper specs. Those glass fuel filters are seldom with much fuel in them. Just the way they are. smile.gif Jim<BR>

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You can purchace a "curve kit" at any speed shop, Jegs, Summit, Etc. Just install the new springs for a quicker timing advance. I am using the lightest ones on my street car. On a race car you might want to use a heavier set to keep traction under control. Total timing is easiest to set with an adjustable timing light. Aim the light at TDC on the balancer while another person slowly increases the RPM. The person with the light will be adjusting the dial trying to keep it on the TDC mark untill it doesn't advance any more (1600 RPM on my car). You adjust the total by moving the distributor. It's very important that you have no more that 30 degrees total on a Nailhead. Any more and the power starts to drop off. This will give the car quicker response, more power, and maybe better mileage (if you can keep your foot out of it). grin.gif Jim <p>[This message has been edited by nailvalve (edited 11-27-2000).]

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The "jerking" may be related to the carb starting problems. A lean condition may cause that condition. Maybe a carb o-haul is in order? <BR> Don't mess with the weights. And yes, the dist vac advance seems to be doing its job. Always disconect the advance when setting or checking your timing. If you set your dist up like I suggested above, you should have about 5 degrees at idle. The reason I set the timing for TOTAL is that the Nailhead puts out the maximum power at 30 degrees. I've never seen an exception to this. By the way...What model Edelbrock intake are you using? If its a B262 2x4bbl, the dist vac line goes to PRIMARY carb. <p>[This message has been edited by nailvalve (edited 11-27-2000).]

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First of all..It's an Edelbrock not an eldenbrock carb. Do you know what part # or CFM you have? Why was it rejetted? The best and quickest way to properly jet a carb is to find a local chassis dyno shop. Be sure that they are familiar with your model carb before letting them work on it. smile.gif Jim

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I had a question regarding the 30 deg. of total timing recommendation. I have the 401 in my 1966 GS, which is all stock except for a Keene Bell Mk1 camshaft. K-B recommended that I set the total timing at 35 deg, which comes in at around 2800 with my distributor setup. Just wondering where you get the 30 degrees total recommendation from. I'd like to get more power out of my combination, so any advice would be great.<BR> Also, do you have any problems with all the centrifugal advance coming in at 1600? No pinging or any bad effects?

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Besides a lot of feedback over the years, two quick sources for the timing setting are: April 1966 Hot Rod Magazine did an article called Blueprint for Buicks. Using "Pop" Kennedy and three other Buick racers as the source. And also Street Rodder did a dyno test on a 401 in August 1997. The 35 degree setting would be ok for a 455. I'm getting no pinging on 92 octane and can break the tires loose when I nail it @ 25 mph. That's with 2.93 rear gears!

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my eldebrock carb is a 600cfm. the mechanic who got the newly rebuilt engine running suggested a smaller carb with larger jets. maybe he just had a 600 laying around. it was brand new though. could it hurt to just buy the stock jets and put them in and see what happens? is it easy to change them?

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Hey Nailvalve,<P> I'll reset my total timing and let you know how it works. I'll swap in a set of lighter springs, too. I know my car ought to feel more powerful with some more tuning. Thanks-

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Justin, I would suggest getting another carb. 600cfm is just too small for a 401! For a good all around street carb 750 is ok and for street/strip at least 800cfm should be used. Changing the jets doesn't change the air flow. I wouldn'd waste my time or money fooling with the carb you have. frown.gif

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my problem is : I dont know what the car should feel like. its a 65 riv. I am so used to 4-6 cyl that I cant tell if the 401 is running well or not. it seems fine , fast , powerful as hell. but it has to be pumped to start when it is hot. and it smells like it is running too rich. after I got the timing correct, I plan on leaning out the carbs or going with smaller jets.

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